Since pheochromocytoma may produce adrenocorticotropin, insulin-like growth factor 2, somatostatin, growth hormone-releasing hormone, corticotropin-releasing hormone, and interleukin 6, it was considered, however, that it might also stimulate the adrenal cortex to hyperfunction and proliferation through the paracrine pathway (21). This evidence concerns the gene IL6 and pheochromocytoma.